Except the UK has appointed a child as their PM and is at the moment throwing a "we're not doing any cooperation!" tantrum.

China could just dangle the promise of a post-Brexit trade deal (the Brexiters need anything to look good, they were ready to brag about deals with S. Arabia and Turkey).

As someone has mentioned, imagine if Le Pen wins in France, the UN Security Council would be run by Xi, Putin, Trump, BoJo and Le Pen...